Spring leaf

ABSTRACT

A spring leaf comprising an integral substantially cylindrical eye structure on at least one of its ends consisting essentially of adjacent parallel portions cylindrically curved in opposite directions out of the plane of the leaf.

Unite Sites atom Rowland 1 Feb.29,11972 [54] SPRING LEAF [72] Inventor:Frederick T. Rowland, Birmingham, Mich.

[73] Assignee: North American Rockwell Corporation,

Pittsburgh, Pa.

22] Filed: 11111121.,1970

[21] Appl.No.: 42,290

[52] US. Cl ..267/54, 267/47, 29/173, 72/362 [51] Int.Cl ..B60g11/02,F16f1/18 [58] Field of Search ..267/47, 54; 16/128, 171, 172,16/178; 72/362; 29/1 1, 173, 434

[56] References Cited I UNITED STATES PATENTS 2,682,399 6/1954 Imblum..267/47 2,510,418 6/1950 Roehrig ..267/47 2,932,056 4/1960 Crosswell16/ l 71 2,608,752 9/1952 Schilling ..267/47 941,521 11/1909 .letfrey..267/55 7 2,568,169 9/1951 Raczynski.. ..29/173 3,389,902 6/1968 Young..29/173 FOREIGN PATENTS OR APPLICATIONS 455,167 l/1928 Germany ..267/47592,558 5/1925 France ..267/52 Primary Examiner-Drayton E. HoffmanAttorney-John R. Bronaugh, Floyd S. Levison, E. Dennis O- Connor andRichard A. Speer [5 7] ABSTRACT A spring leaf comprising an integralsubstantially cylindrical eye structure on at least one of its endsconsisting essentially of adjacent parallel portions cylindricallycurved in opposite directions out of the plane of the leaf,

9 Claims, 13 Drawing Figures Patented Feb. 29, 1972 2 Sheets-Sheet 1INVEN TOR.

FREDERICK T. ROWLAND Patented Feb. 29, 1972 2 Sheets-$heet 2 INVENTORFREDERICK T. ROWLAND SPRING LEAF This invention relates to spring leafstructure and particularly to the end formation commonly known as theeye for connecting the spring end or ends to frame pivots, shackles andthe like.

It has been generally conventional to form these spring eyes integralwith the spring leaf by suitably turning over the spring end. to providea cylindrical bosslike formation adapted to fit over .the pivot orshackle pin. In this conventional eye formation, the eye may be disposedabove or below the plane of the leaf, usually above, or with its centerin the plane of the leaf which is the so-called Berlin eye. In allforms, the entire leaf end is. reversely turned over in a rolling orequivalent opera tion until the end edge substantially abuts a leafsurface.

Difficulties have been encountered in these conventionally formed eyesbecause the entire width of the leaf is curved in one direction and theeye under driving and braking leads is subjected to bending moments.These bending moments tend to open and otherwise deform the eye andcreate bending stresses of high magnitude. Since bending stresses arehighest at the surface of the leaf, stress raisers and abrasion at thesurface are very critical to fatigue life.

The major object of the invention is to provide a novel spring eyestructure wherein the stresses are distributed across the section of theleaf by substantial elimination of the bending moments during operationof the vehicle.

More specifically the present invention contemplates reducing theforegoing difficulties by providing a novel leaf spring eye structurewherein integral parallel oppositely curved end portions form the springeye and this is another object of the invention.

It is further object of the invention to provide a novel leaf spring eyestructure of cylindrical contour wherein adjacent spring leaf endportions are oppositely uniformly curved about a common center.

Another object of the invention is to provide a novel integral leafspring eye structure consisting of adjacent oppositely curved endportions which have their terminal edges adjacent and facing each othernear the juncture between the spring eye and the leaf.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a side elevation showing aspring leaf according to a preferred embodiment of the invention;

FIG. 2 is a partly broken away fragmentary side elevation showing oneend of a spring leaf formed according to the invention;

FIG. 3 is end view of the spring leaf of FIG. 2;

FIG. 4 is top plan view of the spring leaf of FIG. 2;

FIG. 5 is a fragmentary side elevation of a spring end illustrating afurther embodiment;

FIG. 6 is an end view of the spring of FIG. 5;

FIG. 7 is a fragmentary plan view showing the spring end of FIG. 5.

FIG. 8 is a fragmentary side elevation showing an end of a spring leafformed according to a further embodiment;

FIGS. 9 and w are respectively plan and end views of the spring end ofFIG. 8;

FIG. 11 is a fragmentary side elevation showing an end of a spring leafformed according to a still further embodiment; and

FIGS. 12 and 13 are respectively plan and end views of the spring end ofFIG. 11.

PREFERRED EMBODIMENTS FIG. 1 shows a single tapered spring leaf l1incorporating the invention. The spring leaf is preferably an integralmember of some alloy steel or carbon steel or other suitable materialconventionally used for vehicle springs. This spring leaf may be of thetype having a center section 12 of maximum thickness, usually mediallysecured to an axle indicated at A, and end sections that graduallyreduce in thickness from the center section toward the spring ends.Preferably the spring leaf is of constant width from end to end, and isof uniform size at the opposite end sections. Spring leaf ll has a flatplanar surface 14 along its entire length at one side, and at the otherside the tapered surfaces 15 and I6 extend at an angle relative tosurface 14.

Spring leaf llI may advantageously be the tapered leaf spring disclosedinGreene et a]. U.S. Pat. No. 3,238,072, and made by the methoddisclosed in that patent, including forming surfaces 15 and 16 by rolltapering, except that the spring ends in the present invention areformed in a novel manner to provide a novel spring eye structure as willappear. The invention may be applied to any spring leaf, including forexample the types disclosed in Komarnitsky U.S. Pat. No. 3,339,908, andSchilling Pat. No. 2,608,752, and the top leaf of an otherwiseconventional multileaf spring bundle.

Referring to FIGS. 2-4, there is shown one end of spring leaf Ill. Theother end is preferably identical. The spring end is integrally formedto provide an eye structure 117 adapted to connect the spring end to apivot on the chassis C or on a shackle S (FIG. I)

The integral eye structure 17 consists essentially of a central endportion 18 of the spring end bent upwardly out of the plane of the leafin a smoothly curved junction I9 and then counterclockwise outwardly,downwardly and back inwardly around in substantially circular curvatureto locate its terminal edge 20 adjacent the underside of the leaf atjunction I9. Two spring end portions 21 and 22, of the same length asportion l8 and disposed on opposite sides of portion 18, are similarlybut reversely bent downwardly out of the plane of the leaf in a smoothlycurved junction 23 and then upwardly around in a substantially circularcurvature to dispose their terminal edges 24 adjacent the supper side ofthe leaf adjacent junction 23, Junctions I9 and 23 are adjacent andidentical but oppositely curved.

As shown the leaf end portions 211 and 22 are each of about one-half thewidth of central portion If}. The inner surface 25 of leaf end portionI8 is a cylinder having its center on the longitudinal axis of the leaf,and the inner surfaces 26 of the outer side portions 21 and 22 arecylinders of the same radius about the same center. Thus the cylindricalsurfaces 25 and 26 which have a common center define an eye structureadapted to pivotally fit over a bushing, a chassis mounted pivot orshackle pin in the usual manner.

Preferably the spring eye 17 is formed by cutting parallel slits 27 and28 of equal length and proper lateral spacing at the ends of theotherwise complete spring leaf, and then subjecting the end portions 18,2ll and 22 to a suitable rolling or equivalent forming operation toprovide the cylindrical eye structure.

It will be understood that if desired the cylindrical eye can be formedby reversely bending the central and side end portions of the leafrespectively oppositely to the above described directions.

FIGS. 5-7 illustrate another embodiment of the invention wherein thecylindrical eye structure 29 is formed above the level of the leaf 11.In this embodiment the central end portion 31 is bent upwardly out ofthe plane of the spring leaf in a smoothly curved junction 32 and thenoutwardly, downwardly and back inwardly to dispose its terminal edge 33adjacent junction 32. The two equal width end portions 34 and 35 onopposite sides of central portion 31 extend past junction 32 and arereversely bent in a substantially circular clockwise curvature upwardout of the plane of the leaf and then inwardly and downwardly to disposetheir terminal edges 36 adjacent juncture 32 and substantially in thesame radial plane as edge 33.

The cylindrical inner surface 38 of leaf end portion 31 has the sameradius as the coaxial cylindrical surfaces 39 of the end portions, sothat a cylindrical eye structure is provided at 29 for pivotalconnection to the chassis or shackle as in FIG. 1.

It will be understood that if desired the eye 29 may be formed bycurving the central and end portions respectively oppositely to theabove-described directions, or by curving these central and sideportions to dispose the cylindrical eye on the underside of the springleaf.

FIGS. 8-10 illustrate another embodiment wherein the cylindrical eyestructure 40 is formed of two oppositely curved adjacent end portions 41and 42 instead of three as in FIGS. 2-4. Here the spring leaf end islongitudinally slitted back from the end edge a suitable amount, thisslit being preferably medial as indicated at 43. The end portion 41 atone side of the slit is bent upwardly out of the plane of the leaf in asmoothly curved junction indicated at 44, and the other end portion 42is bent downwardly out of the plane of the leaf in a smoothly curvedjunction indicated at 45.

The reversely curved end portions 41 and 42 have aligned coaxialcircularly cylindrical inner surfaces 46 and 47 respectively, and theterminal edges 48 and 49 of the respective end portions face each otheradjacent the juncture of the eye with the leaf.

FIGS. 11-13 illustrate another embodiment wherein the cylindrical eyestructure 50 is formed of two oppositely curved adjacent end portions 51and 52, instead of three as in FIGS;

-7. Here the spring leaf end is longitudinally slitted back from the endedge a suitable amount, this slit being preferably medial as indicatedat 53. The end portion 51 at one side of the slit is bent upwardly outof the plane of the leaf in a smoothly curved junction indicated at 54,and then outwardly, downwardly and back inwardly to dispose its terminaledge 55 adjacent junction 54. The other end portion 52 is reversely bentin a circular clockwise curvature upwardly out of the plane of the leafand then inwardly and downwardly to dispose its terminal edge 56adjacent juncture 54 and substantially in the same radial plane as edge55.

The reversely curved end portions 5 and 52 have aligned coaxialcircularly cylindrical inner surfaces 57 and 58 respectively.

In all embodiments of the invention the eye consists essentially of atleast two side-by-side adjacent oppositely curved end portions of thespring leaf. Preferably in all embodiments the total cylindrical innerbearing areas curved in opposite directions are substantially equal.

The invention may be embodies in other specific forms without departingfrom the spirit or essential characteristics nnlum thereof. The presentembodiments are therefore to be considered in all respects asillustrative and not restrictive, the scope of the invention beingindicated by the appended claims rather than by the foregoingdescription, and all changes which come within the meaning and range ofequivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by Letters Pat. is:

l. A spring leaf comprising an integral substantially cylindrical eyestructure located at least at one of its ends consisting essentially ofadjacent end portions curved in opposite directions out of the plane ofthe leaf, the terminal edges of said spring end portions being disposedadjacent the juncture of the eye structure with the leaf.

2. A spring leaf as defined in claim 1, wherein at least one of springend portions is connected to the leaf by a smoothly curved junction andthe terminal edges of all of said spring end portions are disposedadjacent said junction.

3. A spring leaf as defined in claim 1, wherein the total internalbearing surface area of the portions curved in one direction are equalto the total internal bearing surface areas of the portions curved inthe opposite direction.

4. A spring leaf as defined in claim 1, wherein said eye structurecomprises an intermediate end portion curved in one direction out of theplane of the spring leaf, and adjacent opposite side edge portionscurved in the opposite direction out of the plane of the spring leaf.

5. The spring leaf defined in claim 4, wherein said intermediate portionis centrally disposed and of approximately twice the width of each sideedge portion.

6. The spring leaf defined in claim 4, wherein said intermediate andside edgecportions are of the same length.

7. The spring lea efined in claim 4, wherein said intermediate portionis connected to said leaf by a smoothly curved junction, and theterminal edges of all of said portions are disposed adjacent saidjunction.

8. The spring leaf defined in claim 1, wherein said eye structurecomprises two side-by-side cylindrical portions oppositely curved out ofthe plane of said spring leaf.

9. The spring leaf defined in claim 8, wherein said curved end portionsare of substantially equal width.

E UNiTEDsTATEs PATENT OFFICE.

cnimm'm @F 3,645,522 Dated .February 29, 1972 Patent No.

inventor) FREDERICK To ROWLAND It is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

Column 2, line 33, change "supper" to read "upper" Column 3, line 32,change numeral "5" to numeral "51" Signed and sealed this 8th day of May1973o (ISL-ll) Attest:

LJDWARD IEJEETCHERJER. ROBERT GOTTSCHALK "'ztesting Officer Commissionerof Patents

1. A spring leaf comprising an integral substantially cylindrical eyestructure located at least at one of its ends consisting essentially ofadjacent end portions curved in opposite directions out of the plane ofthe leaf, the terminal edges of said spring end portions being disposedadjacenT the juncture of the eye structure with the leaf.
 2. A springleaf as defined in claim 1, wherein at least one of spring end portionsis connected to the leaf by a smoothly curved junction and the terminaledges of all of said spring end portions are disposed adjacent saidjunction.
 3. A spring leaf as defined in claim 1, wherein the totalinternal bearing surface area of the portions curved in one directionare equal to the total internal bearing surface areas of the portionscurved in the opposite direction.
 4. A spring leaf as defined in claim1, wherein said eye structure comprises an intermediate end portioncurved in one direction out of the plane of the spring leaf, andadjacent opposite side edge portions curved in the opposite directionout of the plane of the spring leaf.
 5. The spring leaf defined in claim4, wherein said intermediate portion is centrally disposed and ofapproximately twice the width of each side edge portion.
 6. The springleaf defined in claim 4, wherein said intermediate and side edgeportions are of the same length.
 7. The spring leaf defined in claim 4,wherein said intermediate portion is connected to said leaf by asmoothly curved junction, and the terminal edges of all of said portionsare disposed adjacent said junction.
 8. The spring leaf defined in claim1, wherein said eye structure comprises two side-by-side cylindricalportions oppositely curved out of the plane of said spring leaf.
 9. Thespring leaf defined in claim 8, wherein said curved end portions are ofsubstantially equal width.